Matt Damon Loves George Clooney's Girlfriend

George Clooney's newest squeeze has passed an important test: gaining the approval of her beau's friends.

"She is a really, really wonderful woman," Clooney's close pal Matt Damon, 38, told PEOPLE at Tuesday's Manhattan premiere of his film The Informant!

Damon says he and wife Luciana vacationed this summer with the Oceans Eleven star and his new girlfriend, Elisabetta Canalis, 30. And apparently Canalis, an Italian TV presenter, is having a good effect on Clooney, 48.